I have had oozes at the post/qd interface a couple times. once because as the qd got turned this way and that it loosened the post enough to allow beer past the seal. The second time was with water (Thankfully) and was because I had the pressure cranked in an attempt to get sparkly water to the masses quicker and the cobra tap and/or QD was not able to resist that much pressure (around 35 PSI)

It's funny because I would do that. In December I didn't think the poppet on full pressurized keg looked right, so I pushed down to re-seat it. Face-full of beer. It was a shameful walk back into the house.